1. Index Fossils & The Fossil Record
More Rock Layer Practice!!!
Put these in order.
Which rocks do you think are igneous?

2. Almost all fossils are discovered in sedimentary rock.
The fossil record provides information about the geologic history of Earth.
Scientists can use this information to learn about how environmental changes have affected living organisms.

3. What periods during the Paleozoic were trilobites first present?
What period during the Mesozoic were dinosaur fossils first present?
How many years ago was that?

4. Index Fossils
Index fossils can provide the relative age of a rock layer.
existed only during specific spans of time
occurred in large geographic areas
Index fossils include fusulinids and trilobites.

5. Index Fossils
Index fossil - a fossil that is used to establish the age of rock layers because it is distinct, abundant, and widespread and existed for only a short span of geologic time.
Ammonites, picture an octopus with a shell, are well known as index fossils

7. How do scientists determine what fossils are index?
a fossil must be present in rocks scattered over a large region
it must have features that clearly distinguish it from other fossils.
organisms from which the fossil formed must have lived during a short span of geologic time, and the fossil must occur in fairly large numbers within the rock layers.

8. Index Fossils & Absolute Age
Scientists can use index fossils to estimate absolute ages of specific rock layers.
Because organisms that formed index fossils lived during short spans of geologic time, the rock layer in which an index fossil was discovered can be dated accurately.
Scientists can also use index fossils to date rock layers in separate areas.
Index fossils are used to help locate rock layers that are likely to contain oil and natural gas deposits.

9. Fossil Record Lab
Read instructions on worksheet and in groups complete Table 1.
Give Fossil Samples sheets back to teacher.
Then independently complete the 2nd page involving analysis of what you found.
Please hand in for grade.

10. Discovery Education Activity
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Complete the activity until you find all the index fossils. The first stage will give you one!
Index Fossil
Period